Generally, epitaxial growth includes a chemical vapor deposition process and a substrate such as a single crystal silicon wafer is heated while a silicon compound in a gaseous, liquid, or solid state is transferred through a surface of the substrate and affects thermal decomposition or decomposition. When the single crystal silicon wafer is used for the substrate, silicon is stacked by continuously growing a single crystal structure. Thus, defects such as a cohesion silicon self-gap defect, or the like, which exist on the surface of the substrate, may directly affect quality of an epitaxial wafer. In the effect on the quality, the defects which exist on the surface of the substrate is continuously grown together with continuously growing the single crystal structure, and thus this may cause forming of a new crystal defect, that is, a growth defect in an epitaxial layer. For example, a surface defect such as an epitaxial stacking defect and a hillock in a range of about 0.1 microns to 10 microns may be formed. Therefore, a method and process of fabricating a substrate which does not substantially have such a surface defect problem is required in an epitaxial growth process.
Further, it is important that the doped epitaxial wafer has doping uniformity from a center to an edge, which meets a desired range according to the design specifications. Therefore, a method and process of fabricating the epitaxial wafer capable of improving the doping uniformity is required.